Small water vehicles such as pontoon boats are commonly used for recreational and business purposes in rivers and lakes. A pontoon boat includes a passenger compartment or platform set on elongated floats called pontoons. A motor is positioned between the pontoons. The pontoon boat relies on the large flotation capacity of the pontoons to provide buoyancy and stability to the watercraft—the pontoon surfaces both absorb and generate waves, permitting large loads and travel across turbulent water.
Pontoon water vehicles may be gas powered or electrically powered. Originally, electric engines were more reliable than gasoline engines; however, the technology of gas engines improved at a faster rate, providing more horsepower and reliability than electric engines. Eventually, the state of the art was such that electric engines could not compete with gasoline engines. Unfortunately, the success of gasoline powered boating has brought environmental damage to the very waters and ecosystems that support the enterprise. Environmental repair to water and areas of boating has been accommodated by the removal or restriction of gasoline powered boats and the promotion of electric boats.
Electrically driven water vehicles, however, still present engineering challenges. Electric boat motors consume large amounts of DC power to move a load over water, so large battery packs are required for their operation. To compensate for this size, battery packs have traditionally been placed on the deck of the vehicle. Doing so provides ample space for large packs; however, this creates a craft having a high center of gravity, which affects the trim (equilibrium) of the craft. In addition, situating battery storage on the deck not only restricts passenger activity (since it takes up a large portion of the deck area), but also makes the battery easily accessible by passengers. Since electrically driven boats require the use of AC/DC electrical wires on or near the water for recharging, storing batteries on a deck risks serious injury to passengers (e.g., electrocution or serious burns caused by passengers accessing the batteries). Consequently, there is a need to provide a watercraft that can accommodate large battery loads, free up deck space, and limit the accessibility of the battery storage area to passengers.
One approach to addressing these concerns is shown in U.S. Pat. No. 6,000,353 (De Leu). De Leu discloses a recreational raft having a hand-controlled steering mechanism and solar cells for powering an outboard electric motor. A chair forms a raft interconnecting a pair of sponsons to each other. Each sponson extends outward from a side of the chair. The sponsons have flat, upward facing surfaces each including a photovoltaic cell connected to a control panel. An optional battery is encased within one sponson. An electric propeller motor, positioned rearward of the chair, is supported by a tube attached between the rear of the sponsons.
U.S. Pat. No. 6,073,569 (Motsenbacker et al.) discloses an electric powered watercraft comprising a power mass completely enclosed in a support member that further includes the motor. The support member is mostly or completely submerged in the water. The watercraft further includes at least one floating ski configured to skip along the surface of the water, providing buoyancy to the watercraft. A platform is spaced above the support member and ski(s) using struts.
Both of the above approaches suffer from several disadvantages. The sponsons of the single person raft of DeLeu are positioned laterally from the passenger seat. As a result, should the raft contact side-rolling waves, the raft will become unstable, making it unsuitable for open waters. DeLeu, moreover, requires the battery source to be completely enclosed within the sponson, limiting access thereto. Any corrosive gasses or chemicals released by the battery would corrode and destroy the sponson, requiring its replacement. The enclosed power source, furthermore, must remain small—enclosing a larger weight (i.e., a larger battery) within either sponson creates additional raft instability.
Motsenbacker et al., while enabling access to open waters, similarly requires its battery source to be completely enclosed within the support member. This not only prevents access to the power source from the deck, but any corrosive gasses or chemicals released by the battery would corrode and destroy the support member, requiring its replacement. In addition, the support member is mostly or completely submerged during use; consequently, a user must dry dock the watercraft to repair or replace components in the support member, since repair during use is impossible.
Consequently, there exists a need to provide a watercraft suitable for open waters including a flotation structure that provides a user access to the battery source, as well as provides increased watercraft stability.